scholarly journals Setting Clock Speed in Mammals: The CK1ɛ tau Mutation in Mice Accelerates Circadian Pacemakers by Selectively Destabilizing PERIOD Proteins

Neuron ◽  
2008 ◽  
Vol 58 (1) ◽  
pp. 78-88 ◽  
Author(s):  
Qing-Jun Meng ◽  
Larisa Logunova ◽  
Elizabeth S. Maywood ◽  
Monica Gallego ◽  
Jake Lebiecki ◽  
...  
Keyword(s):  
Clock Speed ◽  
Tau Mutation ◽  
Circadian Pacemakers

Relationship between circadian period and body size in the tau-mutant golden hamster

2014 ◽  
Vol 92 (1) ◽  
pp. 27-33
Author(s):  
Roberto Refinetti
Keyword(s):  
Body Size ◽  
Single Gene ◽  
Pleiotropic Effect ◽  
Circadian Period ◽  
Golden Syrian Hamster ◽  
Casein Kinase 1 ◽  
Reduced Body ◽  
Short Period ◽  
Casein Kinase 1 Epsilon ◽  
Tau Mutation

The tau mutation in the golden (Syrian) hamster is a single gene mutation that drastically affects the speed of the circadian clock, in such a way that homozygous mutants have an endogenous circadian period of 20 h (compared with 24 h for wild-type hamsters). While studying the circadian system of tau-mutant hamsters during the past 25 years, several authors have noted an apparent relationship between circadian period and body size in these animals. This study, based on 181 hamsters from 24 litters, confirmed previous observations that a shorter circadian period is associated with smaller body size, documented a sex difference in this association, and evaluated several mechanisms that might explain the phenomenon (such as different organ sizes, body composition, and metabolic rate). The obtained evidence suggests that the reduced body size of short-period hamsters is likely a pleiotropic effect of the tau allele (an allele of the casein kinase 1 epsilon gene) rather than a consequence of the shortened circadian period.

Clinical–electrophysiological correlation of tremor and myoclonus in a kindred with the N279K tau mutation

2003 ◽  
Vol 9 (3) ◽  
pp. 151-157 ◽  
Author(s):  
John N Caviness ◽  
Yoshio Tsuboi ◽  
Zbigniew K Wszolek
Keyword(s):  
Tau Mutation

Serotonin sets the day state in the neurons that control coupling between the optic lobe circadian pacemakers in the cricketGryllus bimaculatus

2002 ◽  
Vol 205 (9) ◽  
pp. 1305-1314 ◽  
Author(s):  
A. S. M. Saifullah ◽  
Kenji Tomioka
Keyword(s):  
Neural Activity ◽  
Receptor Agonist ◽  
Serotonin Receptor ◽  
Optic Lobe ◽  
Neural Pathway ◽  
Gryllus Bimaculatus ◽  
Dependent Inhibition ◽  
Serotonin Receptor Antagonist ◽  
Time Dependent Inhibition ◽  
Circadian Pacemakers

SUMMARYThe bilaterally paired optic lobe circadian pacemakers of the cricket Gryllus bimaculatus mutually exchange photic and circadian information to keep their activity synchronized. The information is mediated by a neural pathway, consisting of the so-called medulla bilateral neurons,connecting the medulla areas of the two optic lobes. We investigated the effects of serotonin on the neural activity in this coupling pathway. Spontaneous and light-induced electrical activity of the neurons in the coupling pathway showed daily variations, being more intense during the night than the day. Microinjection of serotonin or a serotonin-receptor agonist,quipazine, into the optic lobe caused a dose- and time-dependent inhibition of spontaneous and light-induced responses, mimicking the day state. The amount of suppression was greater and the recovery from the suppression occurred faster during the night. Application of metergoline, a non-selective serotonin-receptor antagonist, increased spontaneous activity and light-evoked responses during both the day and the night, with higher effect during the day. In addition, metergoline effectively attenuated the effects of serotonin. These facts suggest that in the cricket's optic lobe, serotonin is released during the daytime and sets the day state in the neurons regulating coupling between the bilaterally paired optic lobe circadian pacemakers.

Sites of phosphorylation in tau and factors affecting their regulation

2001 ◽  
Vol 67 ◽  
pp. 73-80 ◽  
Author(s):  
Brian H. Anderton ◽  
Joanna Betts ◽  
Walter P. Blackstock ◽  
Jean-Pierre Brion ◽  
Sara Chapman ◽  
...  
Keyword(s):  
Glycogen Synthase ◽  
Principal Component ◽  
Paired Helical Filaments ◽  
Glycogen Synthase Kinase 3 ◽  
P38 Kinase ◽  
Factors Affecting ◽  
Extracellular Signal ◽  
Mitogen Activated Protein ◽  
Tau Mutation

The microtubule-associated protein, tau, is the principal component of paired helical filaments (PHFs) in Alzheimer's disease. PHF-tau is highly phosphorylated and a total of 25 sites of phosphorylation have so far been identified. Many of these sites are serine or threonine residues that are immediately followed in the sequence by proline residues, and hence are candidate phosphorylation sites for proline-directed kinases. In vitro, glycogen synthase kinase-3 (GSK-3), extracellular signal-related kinase-1 and -2, and mitogen-activated protein kinases, p38 kinase and c-jun N-terminal kinase, all phosphorylate many of these sites, although with different efficiencies for particular sites. Phosphorylation studies in transfected cells and neurons show that GSK-3 phosphorylates tau more extensively than do these other proline-directed kinases. Mutations in tau have been shown to affect in vitro phosphorylation of tau by GSK-3. The Arg406-->Trp (R406W) tau mutation also affects tau phosphorylation in cells.

P3-333 Pathological characterization of two FTDP-17 patients carrying a G272V tau mutation

2004 ◽  
Vol 25 ◽  
pp. S450
Author(s):  
Iraad F. Bronner ◽  
Bastiaan C. ter Meulen ◽  
Wouter Kamphorst ◽  
Rivka Ravid ◽  
Peter Heutink ◽  
...  
Keyword(s):  
Tau Mutation

Special-purpose computing for dense stellar systems

2006 ◽  
Vol 2 (14) ◽  
pp. 424-425 ◽  
Author(s):  
Junichiro Makino
Keyword(s):  
Current Status ◽  
Stellar Systems ◽  
Double Precision ◽  
Next Generation ◽  
Single Chip ◽  
Clock Speed ◽  
Peak Speed

AbstractI'll describe the current status of the GRAPE-DR project. The GRAPE-DR is the next-generation hardware for N-body simulation. Unlike the previous GRAPE hardwares, it is programmable SIMD machine with a large number of simple processors integrated into a single chip. The GRAPE-DR chip consists of 512 simple processors and operates at the clock speed of 500 MHz, delivering the theoretical peak speed of 512/226 Gflops (single/double precision). As of August 2006, the first prototype board with the sample chip successfully passed the test we prepared. The full GRAPE-DR system will consist of 4096 chips, reaching the theoretical peak speed of 2 Pflops.

The Physiology of Circadian Pacemakers

1978 ◽  
Vol 40 (1) ◽  
pp. 501-526 ◽  
Author(s):  
M Menaker ◽  
J S Takahashi ◽  
A Eskin
Keyword(s):  
Circadian Pacemakers
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